Avalanche Forecast

Issued: Jan 4th, 2023 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Persistent Slabs.

Avalanche Canada shorton, Avalanche Canada

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A persistent weak layer is present at all elevations and could produce large destructive avalanches if triggered. Careful terrain choices are recommended given the uncertainity about this problem.

Summary

Confidence

Moderate

Avalanche Summary

A few reports of small (size 1) avalanches have been reported since the weekend. Over the weekend and last week, there were several reports of larger (up to size 2.5) natural avalanches at all elevations releasing on a 30 to 60 cm deep facet layer. Triggering an avalanche on this weak layer is still possible under the current conditions.

Snowpack Summary

Exposed terrain has been affected by southerly winds, while sheltered terrain has 10 to 15 cm of low density snow. This snow may sit above a layer of small surface hoar that will sluff easily in steep terrain. A weak layer of facets that formed during the arctic outbreak in December is buried 30 to 60 cm deep. Recent avalanche activity and snowpack tests suggest human-triggering is possible for this layer. We are uncertain about the layer's spatial distribution, but observations suggest it is fairly widespread.

Weather Summary

Wednesday night

Partly cloudy, no precipitation, 30 to 40 km/h wind from the southeast, treeline temperatures drop to -10 °C.

Thursday

Mix of sun and cloud with isolated flurries bringing trace amounts of snow, 20 to 40 km/h wind from the southeast, treeline temperatures warm to -6 °C.

Friday

Cloudy with afternoon flurries brining up to 5 cm of snow, 40 to 70 km/h wind from the southwest, treeline temperatures warm to -5 °C.

Saturday

Mix of sun and cloud, no precipitation, 30 to 50 km/h wind from the south, treeline temperatures around -6 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Caution around convexities or sharp changes in terrain.
  • Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.
  • Avoid making assumptions about this layer based on the presence of aggressive tracks on adjacent slopes

Problems

Persistent Slabs

An icon showing Persistent Slabs

A layer of facets that formed during the arctic outbreak in December is buried 30 to 60 cm deep. This layer produced natural avalanches last week, and recent snowpack observations suggest it could still be reactive to human triggering.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Jan 5th, 2023 4:00PM

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